Rectifiers are easy to check with a continuity tester - they conduct one way but not the other
Connect a continuity tester (diode or ohms scale) connect one meter lead to the battery positive wire and touch each of the three wires of the same color switch the meter leads and check again - you should get continuity one way and the resistances should be relatively close - now connect one meter lead to the ground wire and check to each of the three stator wires - the result should be the same only opposite of the first check - in other words, if you got continuity with the red lead connected to the battery lead, you should get continuity with the black lead connected to ground (I have to put it this way because current flows negative to positive and meter leads are not necessarily red + and black -. Some meters are red - and black +, you have to know your meter. The final test is to connect one meter lead to the battery wire and the other to the ground wire, then switch them - again you should measure continuity in one direction only, but the resistance reading will be appx. double of checking a single lead to each stator wire. If it passes this test, the next test is to check the regulator - that has to be done with a fully charged battery and the charging system connected - with the engine running at about 2500 to 3000 RPM, lights and all accessories turned off, you should see battery voltage climb to 14.8 volts then drop to about 13.2 and climb again to 14.8 then drop to 13.2 - this is the VR cutting in and out to keep the battery fully charged.
Keep in mind, the charging system is not designed to 'charge', but to maintain a charge - the output of the alternator has to be sufficient to supply all the electrical equipment and have enough left over to charge the battery. It's not the output voltage that's important, but the current (amps). Current rises as voltage drops. Current creates heat as it passes through a resistive load. That is what makes light bulbs hot, but increased resistance means you need more voltage to maintain the current flow. As a battery degrades, it's internal resistance goes up. The charging system produces the same energy and if the battery is resisting charging, the current has to be absorbed by other devices. That's one reason if you have a dead battery and try to charge it with the on board charging system, you can burn out lights and other things.
Most old Polaris's could be run without a battery, but if you tried to use the lights, winch or other accessories, they would burn out or be permanently damaged or simply not work at an acceptable level.
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